Portable transponders, employ RFID, Radio Frequency Identification, as the technology used to collect highway tolls, to serve as personal identification for access control, and to provide means for electronic information interchange, such as credit, etc. Passive RFID tags (i.e. tags without internal power sources such as batteries) and wireless cards contain chips, (also known as computer chips, microchips, memory chips) which store identification and other information, such as credit card numbers, financial data, etc. Tags may be applied to items to identify the item in much the same way that bar codes are used for identification purposes. Information is retrieved from a tag as well as the wireless cards of the present invention by an RFID base station or reader when the tag or card is scanned with radio waves by the reader. The tags may draw their power to function from the interrogation field supplied by the base (read/write) station.
Passive tags are described in U.S. Pat. No. 3,713,148, Card Apparatus and System, issued to Cardullo and Parks. In its simplest form the RFID tag or device includes a circuit, typically a silicon chip, although more than one chip may be used in the construction of the RFID device. The circuit is generally connected to an antenna. The RFID device or card may take on a variety of forms including that of a tag, a key fob, or a card. As previously mentioned, a battery may also be employed to extend the range of the device. It is also possible in principle to build devices that function as tags or wireless cards using electrical circuits including only resistors, capacitors and inductors as is well known by those skilled in the art.
Large scale retailers and their suppliers are pursuing Radio Frequency Identification, RFID, tagging for supply chain tracking of goods. Demonstrations of RFID for item tagging will lead to point of sale check out and data collection. For the item tagging application, RFID tags are attached to some part of an item that is being inventoried or is for sale. The attachment may be such that the tag is not visible since the tag may be placed within a container section of the item or packaging material of the item. Removal of the tag after it is no longer useful can become difficult if not impossible for many practical situations. Thus, the tag will in many cases remain attached to the item that has been sold to a customer. This makes it possible for the tag to be read after the point of sale. This in turn leads to a question of the privacy of the purchaser or customer. The issue of privacy is of utmost concern. It is therefore desirable under some circumstances to deactivate or disable the RFID tag after the point of sale without having to physically remove the tag. Deactivation of the tag is one way to assure privacy.
Temporary deactivation of tags may not satisfy privacy concerns. RFID protocol proposals include a kill command that renders the tag inoperable. This kill command is often referred to as a “Privacy” command—which can be used to permanently deactivate the device at the end of its working life, for example as a customer leaves a store. However, there are two problems associated with the kill command. First, the execution of a kill command may be only protected by a short password, 32 bits for example. Organizations using RFID tags are therefore concerned that unauthorized people may (easily) be able to deactivate them even before point of sale. Second, consumers are afraid that the kill command may not permanently “destroy” a tag. The entity who made the tag may also have means to reactivate it.